Using Johansen-Juselius cointegration technique we examine the stabili
ty of the M1 and M2 real demand for money in Japan using quarterly dat
a over the current floating exchange rate period. With four lags in th
e estimation procedure, it is shown that for the stability of M2 (but
not M1) demand for money it is necessary to include the effective exch
ange rate of the yen. Although the results were sensitive to the choic
e of lags, there was evidence of more cointegrating vectors in M2 than
M1 when the effective exchange rate was included in the cointegrating
space.